1. Field of the Invention
The present invention relates to a slotless brushless DC motor employing a slotless stator core so that no cogging force is produced and a coil arrangement capable of producing a uniform electromagnetic torque.
2. Description of the Prior Art
Conventional axial gap type motors and inner rotor type motors having a permanent magnet rotor which rotates inside a stator core are brushless DC motors which produce no cogging force. However, the axial gap type of motor has a number of disadvantages including: (1) the rotor has a large moment of inertia, (2) the rotor generates noise when rotated at a high speed, (3) the motor is unable to produce a uniform torque when fabricated using a conventional structure in which the coils are arranged or the rotor is magnetized in a fan-shape. An inner rotor type brushless DC motor employing a toothed plastic bobbin for winding coils has the disadvantage that the air gap is large, and hence the permanent magnets of the rotor are unable to function efficiently.